Thanks, I wasn't sure. Reverse is out of mine so I may just look for a reman and go that routeYes and no. The 99 most likely will not have the mounting bolt hole at the 12 o clock position meaning you'll only have 5 bolts in instead of 6. Also if you ever need parts for it in the future, there was ALOT of inprovements mid year 99, then again around 03 GM made another round of changes. I personnally would stick to looking for a 4l80e from behind an LS if it was mine.